Complex lead phthalate-containing compositions and process for preparing same



Patented July 22, 1947 UNITED STATES PATENT OFFICE COMPLEX LEAD PHTHALATE-CONTAINING COMPOSITIONS AND PROCESS FOR PRE- PARING SAME of New Jersey No Drawing. Original application September 11, 1943, Serial No. 502,067. Divided and this application Marchl5, 1946, Serial No. 654,802

8 Claims. 1

The present invention relates to new and useful complex' salts containing lead phthalate and a jlead salt of a monobasic saturated aliphatic acid.

This application is a division of our co-pending :application Serial No. 502,067, filed September 11, 1943.

An object of the present invention is to produce novel double salts having pigmentary value.

:Such'double salts may be employed either alone ior'in combination with other pigments in formuj-lating improved paint compositions. Other ob- ;jects will become apparent from this description of the invention. In. our co-pending application, Serial No. 502,- l)66, filed September 11, 1943, we have described a process for making lead salts of phthalic acid. The present invention is based upon the discovery thatif stoichiometric quantitie of a monobasic saturated aliphatic acid, corresponding to the general formula, CnHZn-I-lCOOH, be introduced in the general method of preparing lead phthalates disclosed in the said co-pending application, complex salts will be formed, corresponding to the following general empirical formulae:

' (Type A) 4PbCsH4(COO) 2.Pb(CnH2n+1CO0) 2 According to the present invention compounds classifiable under Type B have been prepared as follows:

ll 'Basic'lead phthalate-lead acetate 7 PbO.2PbCeH4(COO) 2.Pb (0113000) 2 2. Basic lead phthalate-lead propionate V bO.2PbCsH4(COO)2.Pb(CzH5COO)z a. Basic lead phthalate-lead butyrate PbO.2PbC6I-I4(COO)2.Pb(C3H7COO)2 4. Basic lead phthalate-lead isobutyrate rbo'zrbcsrmcoo)arbtcanqcoon I 5. Basic lead phthalate-lead caproate Pb O.2PbCeH4(COO)2.Pb(C5H11COO)a Basic lead phthalate-lead caprylate Q PbO.2Pb6H4(COO) 2.Pb (C9H19COO) 2 I Basic lead phthalate-lead stearate V PbO.2PbCsH4(COO)2.Pb(CrzHasCOO)2 8'. Basic lead phthalate lead, 2 ethylbutyrate h rbozrbcimoom lama) zcncooiz l It will be noted from the above enumerated compounds that the present invention is applicable for the preparation of complex lead salts of phthalic acid and normal, isomeric and substituted monobasic saturated aliphatic acids.

The method of the present invention comprises bringing together in aqueous media the primary reactants; lead monoxide, phthalic acid, or anhydride, and the monobasic acid, whereby a, reaction occurs with substantially complete recovcry of the complex lead compound in the form of a white precipitate which is sparingly soluble in water. i I

- The manner of bringing the primary reactants together in the aqueous media is not critical. For instance, the phthalic acid (which expression is meant to include phthalic anhydride) may be dissolved in hot water and the hot solution added gradually, preferably with stirring, to an aqueous suspension of lead monoxide and saturated aliphatic acid, or the reactants may simply be mixed with water. Occasionally it may be found desirable to charge the reactants, mixed with water, into a ball, or pebble, mill or similar apparatus in which the reaction is allowed to take place.

The reaction may be carried out at any convenient temperature between about 15 C. and. 100 C. In selecting the manner of mixing the reactants together and the temperature at which the reaction is to be carried out, the character of the monobasic saturated aliphatic acid should be considered. Where, as is the case in compounds 1-4 inclusive, listed above, the saturated aliphatic acid is water soluble, a ball mill need not be employed, but the reactants may be mixed with water in any suitable vessel. In such case the employment of an elevated temperature, say between about C. and about C., hastens completion of the reaction. However, where the saturated aliphatic acid is not soluble in water but remains solid or gummy, as is the case with compounds 5-8,'inclusive, listed above, it is preferable to charge the reactants mixed with water into a ball or pebble mill and conduct the reaction at room temperature, say between about 15 C, and 25 C. When an elevated temperature is employed the reactants are kept in contact with each other in the aqueous media, preferably under agitation, until the reaction is completed which usually requires between about 3 hours and about 8 hours. When the reaction is carried out at room temperature, a longer period of time is generally required, sometimes as mucha's 18 or 20 hours.

The following examples are given to illustrate, but not tolimit the present invention.

EXAMPLE 1 Basic lead phfhalate-lead acetate- Pb'O.2PbC6H4(COO) z.Pb(CH3COO) 2 89.3 grams (.4 mol) of finely powdered lead monoxide, PbO, were suspended in 1200 cc. of water containing 15 grams of 30% acetic acid (equivalent to .1 mol of acetic anhydride). The suspension was agitated and heated to 7080 C. A solution of phthalic acid made 'by dissolving 29.6 grams (.2 mol) of phthalic-anhydride in 300 cc. of boiling water was gradually added to the suspension over a five hour period. The resultant white product was filtered, washed with 2 liters of hot water, and dried at 85 C. Theyield was substantially complete; and the product contained 57.5% lead phthalate, 25.2% lead acetate and 17.3% of combined basic lead oxide. Its specifiogravity was found to be 3.73.

7 EXAMPLE 2 Basic lead phthalate-lead propionate- PbO.2PbC'sH4(COO) 2.Pb (C2H5000) z A suspension containing 89.3 grams of finely powdered lead monoxide, PhD, in 1200 cc. of water containing 15.60 grams'of 95% propionic acid wasagitated at 7075 C. and treated over a five hour period with a solution of phthalic acid prepared by dissolving 29.6 grams of phthalic anhydride' in about 300 cc. of boilingwater. The white product, on filtration, washing and drying at 85 C. contained 56.3% lead phthalate, 26.8% lead propionate and 16.9% of combined basic lead oxide. Its specific-gravity was found to be 3.32.

EXAMPLE 3 Basic lead phthalate-lead butyrate- PbO.2PbC6H4(COO) 2;Pb(CaH7C'OO) 2 89.3 grams of finely powdered lead monoxide was added'to 1200 cc. of Water containing 17.6 gramsof normal'butyric acid. The mixture was agitatedand he'ated'to 70-75 C. A'solution of phthalic acid prepared by dissolving 29.6 grams of phthalic 'anhydridein' 600 cc. of boiling water was added'to "thehot suspension "of lead oxide overafivehour period. The white product on filtration; washing and "drying 'at' 85C. contained 55.1% lead phthalate,'31.2% lead'butyrate and 137% of combine'd'basiclead oxide. Itsspecific gravity was found to be 3.15.

EXAMPLE 4 Basic lead phthalate-Zead isobutyrate PbO.2PbC6H4 (C'OO) 2-.Pb(C3H'zCOO)-2 EXAMPLE 5 Basic lead phthalate-lead caproate- PbO.2PbOH4(COO) 2.Pb(CH11COO) 2 A 7 charge comprising '67 grams i powdered. lead monoxide, 22.2 grams phthalic anhydride,17.4 grams of caproic acid and 300 cc. of water was placed in a pebble mill and'ground for 16 hours at room temperature (15-20 C.). The white product which was obtained in complete yield contained no uncombined lead phthalate and did not soften or melt when dried at C. Its specific gravity was found to be 2.86.

EXAMPLE 6 Basic lead phthalate-lead caprylate PbO.2PbC6H4(COO)z.Pb(C9H19COO)2 A charge comprising 67 grams of powdered lead monoxide, 22.2 grams of phthalic anhydride, 21.6 grams of caprylic acid and 300 cc. of water was placed in a pebble mill and ground for 16 hours at room temperature (15-20 C.). The white product, obtained in complete yield, contained no uncombined lead phthalate and did not soften or melt when dried at 90 C. Its specific gravity was found to be 2.61.

EXAMPLE 7 'Basic lead phthalate-Zead stearate PbO.2PbCeH4(COO)2.PD(C17'H35COO)2 A charge comprising 67 grams of .pow'derecl'lead monoxide, 22.2 grams of phthalic anhydride,-.42.6 grams of stearic acid and 300 cc. of water was placed in a pebble mill and ground for 40 hours at room temperature (15-20 0.). The white product, obtained in complete yield, containedno uncombined stearic acid or lead phthalate, and did not soften ormelt when dried at 90 C. .Its specific gravity was'found to be 2.03.

EXAMPLE 8 Basic lead phthalate-lead Z-ethylbutyrate (basic) -PbO.2PbC'sH4(COO) 2PM (C'zHs) zC'HCOOJz A charge comprising 67. grams of powdered lead monoxide, 22.2 grams of phthalic anhydride, 17.4 grams of 2-ethylbutyric acid and 300 cc. of water was placed in a pebble mill and ground for 16 hours at room temperature. The resultant White product obtained in complete yield, containedno uncombined lead phthalate and-.did'not soften or melt when dried at 90 C. Its specific gravity was found to be 3.02.

In preparing the complex lead compounds of the present invention, the reactants are used in the stoichiometric proportions indicated by the formulae for Type A and Type B compounds. The useof proportions other than these may result in products representing incomplete recovery'of the monobasic acid, or the lead phthalate,-or both.

The invention contemplates the preparation of products which are mixtures of Type 'A'compounds with Type B compoundsas wellas mixtures containing lead phthalates, all of which are substantially insoluble in water. For example, mixtures containing monobasic lead phthalate and compounds of Type B may be prepared by using lead'monoxide, phthalic anhydride, and monobasic aliphatic .acid in therespective molar proportions, 2nznz2 where n is 2 'orgreater. than 2. Mixtures of compounds o'f'Type A with normal lead phthalate maybe prepared by using lead monoxide, phthalic-anhydride and aliphatic acid in the respective molar proportions of n:n1:2 where 1!. is 5 or greater than -5. It has been found that compounds of Type B .containthe least amounts oflead monoxide and phthalic acid required to produce insoluble complex lead compounds containing substantially all the aliphatic acid possible in' the system.

While the foregoing. fully describes and illustrates the'present invention, it will'be appreciated by thosesk'illed in the art thatvarious modifications may be made within the scope of the appended claims.

We claim:

-1. A complex lead salt corresponding to the empirical formula PbO.2PbR.PbX2 where R is the phthalic acid radical and X is the radical of a monobasic saturated aliphatic acid corresponding to the general formula CnH2n+1COOH.

2. A complex basic lead phthalate lead acetate salt corresponding to the formula:

PbO.2PbCeH4(COO) 2.Pb(CH3COO) 2 3. A complex basic lead phthalate lead propionate salt corresponding to the formula:

PbO.2PbCeH4 COO) 2.Pb (CHaCOO) 2 4. A complex basic lead phthalate lead isobutyrate salt corresponding to the formula:

PbO.2PbCeH4(COO)2.Pb(C3H7COO)2 5. A process for preparing complex lead salts which comprises mixing together in aqueous media, lead monoxide, phthalic acid, and a monobasic aliphatic acid selected from the group consisting of acetic, propionic, butyric, isobutyric, caproic, caprylic and stearic acids in amounts such that for every 2 molar parts of aliphatic acid there are present 2 molar parts of phthalic acid and 4 molar parts of lead' monoxide and while agitating the mixture, maintaining the temperature thereof between 15 C. and C. until the reaction is substantially complete.

6. A process according to claim 5 wherein the aliphatic acid is acetic acid.

7. A process according to claim 5 wherein the aliphatic acid is propionic acid.

8. A process according to claim 5 wherein the aliphatic acid is isobutyric acid.

ALEXANDER STEWART. ADRIAN R. PI'IROT. LEONARD M. KEBRICH. 

